Up to now, if you wanted to do something about the Technics SL12x0 series tonearm, you either got KABUSA's fluid damper or the Origin Live adapter armboard, enabling mounting of most Rega-mount arms (including the Origin Live line.
If you wanted a better power supply, you could get the one from KABUSA.
Well, there's a new vendor in the UK, Sound Hi-Fi
, a comprehensive British high end vendor who also offers some interesting modifications of the SL12x0 series here
He has armboards for SME and Jelco tonearms. Why no Rega? Owner/operator Peter Cawley doesn't feel that the Rega is a particularly good match for the Technics.
Consider this: When Panasonic released the 1st gen SL1200, they also offered the SL120, the same turntable, but with no tonearm. It came with an armboard for the SME Type III Improved. SME was probably the number one tonearm choice for Technics take-no-prisoners pro model, the SP10.
Peter also likes Technics/Jelco matchups very well. So if you can get ahold of an Audioquest PT6 or PT9 ... Here's a 9-page thread
from mostly last December where an SL1210 enthusiast (who already had several KABUSA mods) introduced Sound Hi-Fi to the Analogue part of the Art of Sound HI-Fi forum in the UK. During this thread he upgraded to a Jelco arm and the review is pretty interesting.
Notice that Peter has his own external power supply, 78 rpm mod, and three different aftermarket feet including the Isonoes. His type 1 feet are actually just Foculpods. Also, his turntable mat is sourced from Herbie's.
Marco's review in this thread mentions the Technics' tonearm's persistent upper midrange "spotlighting", something I usually call "glare." Following that hint, I wrapped some very thin, lightweight plumber's tape (the Teflon kind for sealing threads) around my tonearm including the headshell joint, and voila! The midrange calmed down and with it I got a more relaxed sound with better ambience retrieval and a fuller, yet better defined bass.
Anyway, I recommend you follow the links and do some reading/surfing. I found it quite enlightening to find another pocket of SL12x0 enthusiasts and an alternate source of upgrades and modifications.
Also, notice that Peter sells Avid, SME, Clearaudio, and Marantz turntables, and SME, Jelco, and Hadcock arms, so if he has an axe to grind, it's a pretty broad one.