I'd keep an eye on
this thread and hope they become available again. Or build one yourself. They are really not that difficult to solder and besides it will save you a lot of bucks, as a Rejuv is only about $70 worth of components. I've built two rejuvs in the past and they both worked first time.
As for your NTSC board, is it currently working without daughterboard or has it been sitting there, waiting to be fixed? There is a way to get things running without daughterboard, but it is quite a lot of work and it involves desoldering several chips and transferring one or two original PALs over from the daughterboard to the mainboard below. Also, KS 1.3 needs to be programmed into four 27512 EPROMS.
Full instructions over here.
Pro: Kickstart in ROM, no daughterboard required.
Con: No longer usable with Rejuvenator, unless you restore the current situation.