Not 100% sure but think you should be able to control X10 via your 3950/70 and a converter.
Nevo looks cool but the current version has limitations for controlling a home theater. A new version was supposed to be out 1st qtr 2003 but no sign of it yet. I use PDAWIN as I had already developed a working CCF file with my Philips Pronto. This works very well with only a couple of functions being affected by PDAWIN's repeated button press problem (search the forum for more info on this). V5.4 of PDAWIN works as well as NEVO for ir range with my system.