Rebuilding old Sansui's

I have an old set Sansui speakers from the late 60's or early 70's; the one's with the carved wood grilles, 14" woofers, 5" midranges, piezo tweeters and horn midrange. They have a really substantial cabinet and I was thinking of rebuilding them as a bedroom set.My thought was to keep the horn midrange and tweeters, and replace the crossover, woofer, and cone midranges. Any thoughts on this and if you think it's a good idea, where would I get high quality cone speakers and a crossover?
I guess you have a large bedroom...

Taking a finished speaker design and swapping out components is always a recipe for frustration (unless maybe you can get identical-spec replacement units from the factory.)

Cabinets and crossovers, if properly designed and built, are meant to go with the exact same driver complement and cabinet. Slipping in new same-sized components (to fit the cabinet) doesn't mean they'll just work. However you obviously know this because you are ready to provide a new crossover.

Wow. OK, then. This would be a one-off project. You will need a speaker building expert. Do you have complete specs on the drivers, crossover and cabinet? That would simplify things but your expert will still have to measure the components and systems to make sure they work as specified. Then he (or she) can take the measurements and look for suitable drivers. Then he'll design a crossover to work with them, buy the parts, build and install it and start the listening tryouts.

This last stage could be long or short. If you want some info about it, go to George Short's North Creek site and read up on the design process he describes for some of his models.

The process requires time, deep pockets and more than a bit of luck but anything else would be hit or miss, with a very high chance of a miss. Most folks who try it run out of motivation somewhere before the project is done. Their speaker never sounds right, gets dumped, parted out at giveaway prices or winds up looking for a pigeon in a pathetic ad on kijiji.

I don't want to sound scornful but I would never encourage anyone to try it unless they were already experienced speaker builders and knew just what they were getting into. Myself, I would spend the money on a new speaker--one of Mr. Short's kits would probably satisfy my DIY itch.

All the best anyway if you decide to go for it.
I would keep the woofer because it is really the only driver where the cabinet size is very important. It can be refoamed if need be and this is a DIY project.
I use a pair of Saasui speakers in my garage that are a model or two down from yours but the same vintage. They are very adequate for that purpose, but I am wondering why you want to go to so much effort to restore them. Is it a sentimental thing- I know that many Viet Nam vets bought these Sansui speakers form the PX back in the day. If it is a sentiimental reason, I would say that you should buy another pair off Ebay and cannibalize them for original drivers, and then remove the original crossover and wiring from yours and upgrade the components to modern caps and resistors. As Tobias said, using different drivers from the originals is asking for trouble. Sonic Craft is a great place to get the crossover parts, and good advice.
I just finished rebuilding a pair of Sansui's - mine were a 12" 4 way design. I pulled all of the drivers and x-over, installed a new baffle and built a 8" 2-way system using a basic single order x-over I built from scratch. I had to stuff the cab with added foam, and did everything from trial and error. The result is perfectly adequate, but not state of the art. I also refinished the cab's with tung oil after sanding the veneer really well. They came out looking far better than I expected and I'm very happy with the result given what I put into them. I sold the woofers on Craig's list for what I paid for the speakers. No luck yet selling the other drivers though I haven't tried hard.
I am not expecting anything like what I have for my main system(Martin Logan SL3'S)but I built a pair of speakers years ago that sounded beautiful. I used Radio Shack speakers and crossovers and hand built a large cabinet patterned after Spica t-50's. I would like to find better quality cones that would either fit the original mounting holes or slightly larger and possibly find a better crossover or an adjustable one. I then would like to throw these in the bedroom with maybe a Jolida integrated or other small amp with remote.
if you use good quality components you'll be surprised by the results so long as you match the drivers and have the right crossover. Parts express sells excellent quality components and they tell you all you need to know to do a decent job of matching things up.