Truly High Efficiency, High Quality, Nearfield Usable, Affordable Speakers, Do They Exist?

Trying to help a friend who loves music realize a lifelong dream. He finally has a room all to himself for listening, and wants to put together a SET system. He has acquired, in barter for work, a wonderful 2a3 based SET amp (3.5wpc) and has everything else necessary but the speakers. His room is 10 x 10 x 8, with the limitation that it must also house his desk to operate his business from. So the speakers will be in the nearfield, no more than 5-5.5 feet or so from his listening position, and within a foot to a foot and a half of the front wall, depending on speaker depth His budget requires these speakers to be reasonably affordable (bought used) to maximize his spending. He will be listening to music while working, and also purely listening for pleasure, a good fifty hours a week, so this systems performance is very important to him. 

I'm aware of larger designs, and expensive speakers, though not any that can be used in the nearfield for his needs. Any recommendations, suggestions or expertise in this matter would be immensely appreciated. Thanks.

Have you looked at Omega Super 3i  or Decaware speakers? 
Normally I'm not a fan of whizzer cone single driver speakers, but that is often what is paired with SET's.  

The thing is, for near field listening, you want a point source speaker.  And these single driver speakers are that, so he's in luck in a way.

You can find lots of info from SET zealots on what speakers would be good candidates.  Theres even a brand where you can swap to a better driver in the future.  

The thing is I'd try to get the speakers further away from the wall.  If he could set his desk up so the speakers were 2-3 feet off the wall I think he'd find better sound, even though the speakers would end up being closer to him.  I just personally can't stand hearing the coloration from having speakers near a wall.   
I've heard many very good reports over the years about Omega and Louis. They are certainly in consideration, just not sure if they are quite efficient enough to perform optimally with 3.5 wpc. . Most Omega designs seem to run about 94db. Granted, how accurately companies rate sensitivity is always a concern, the Omega's could be fine? Based on his reputation, I would expect Louis to be forthright about real world sensitivity of his designs.
Honestly, at that distance in that small a room just about any good quality bookshelf/mini-monitor type speaker will do. Especially if he's not out to blow his socks off. Which is not a strength of SET anyway. Listening for quality, inner detail, that spooky-real SET character is gonna come through just fine almost no matter what he uses.

If the room was a lot bigger, or your friend was a lot more experienced, I would offer different advice. But another perfectly good reason for prioritizing sound you like over efficiency and "SET compatible" is he gets going and finds out without too much trouble. One sure way of sucking the fun out of anything is making it harder than it needs to be.

You know another reason, the signal matters more than the speakers anyway. Sorry. But it does. The most awesome SET amp and speakers in the world are not gonna cut it if connected with lamp cord and plugged into rubber freebie power cords. Good wire and peripherals on the other hand (HFT, etc) along with that SET will make just about any speakers perform like he won't believe. 
Altec Model 19's will get the job done with low-power tube amps! Can be found on the used market for around $3K.
The Model 19 is a direct descendant of the Altec Valencia - which I have owned. And a favorite of Art Dudley (Stereophile).
We are looking at Omega speakers. Will also check on your Decware recommendations, although, they apparently also sell Omega speakers, interesting. 
The Omega/Decware pairing is well known on Audio Circle where Omega has a presence:

I use Omega’s Super 3i Monitors with a Decware SE84UFO (2 wpc) in a 13’ x 18’ room. There’s more than enough volume for my taste and listening habits. Your friend’s amp should be just fine.

After a year or so living with the Super 3i’s I added Omega’s DeepHemp 8 Subwoofer to the mix. In my room the sub was a nice addition. Obviously not needed in your friend’s smaller space but if his space changes in the future he can always add a sub if need be.

A pair of Klipsch Heresy 3s will do the job very well. If out of the price range, a pair of series 2s would also be a good fit. I would be happy to discuss a few low cost modifications to get them to the next level. The natural bass roll off would be good in a small square room, and the drivers, being close together, works in a near field situation. As far as efficiency goes, they are as good as you will get. They sound lively, and present a very fun and involving listening experience. Of course, ymmv, but, this is my recommendation. Good luck, and Enjoy ! MrD.
I'll also throw in the Omega speaker recommendation. If your friend is handy there's a ton of 6" and 8" kits that would foot the bill and is pretty cheap. Madisound has a few kits using Fostex Drivers which are really efficient. THe other cool part of single driver speakers is they can be pushed into a corner to help with bass. I started with mine in the corner and started to pull them into the room until it suited my taste bass wise. 
Here's a link to the Madisound Kits

Maybe, if Bob Smith can get it together for a sustained run at his speakers.  They are all that and more.

Bob, not Smith--but I know.
What is the budget?
I have Blumenstein Orca monitors on stands about 5 ft from me. Run them with a 2a3 SET amp, 4 watts. Sweet and musical. Love em!

Keep your radar on PAP. Probably not good for work as work could turn into a complete distraction. Sorry for the bad advice. LOL. Good luck. 
Viking Acoustic Berlin R
The Airtight AL05 sounds fantastic with SET amps. However, I am not sure if it meets the affordability constraint.
I agree with Mr dB.......   Heresy are great for the size and $$$