Hmm. I'd highly doubt that it would ever happen... =/
Yellow was the third installment of the 1st gen games - minor expansion of R/B. It didn't have very many differences in it at all however - the ability to get all of the starters, and so forth, but not too much that made it different from R/B - most of the changes that were done were simply to ride the wave that the anime had going to encourage sales (with the anime having come from the games in the first place, heh). And those games were remade only last get in the for of FR/LG. To remake a game which is basically the original again would be unliekly to yeild all that much in new sales, and profits are the main thing Nintendo look for. Plus - the point of the additions Yellow had would no longer apply. Then it was to endorse the anime/get people to buy it so they can be Ash and get all of the starters and start with Pikachu - but now, that time was long gone. Doesn't quite fit in really - and the anime isn't as big as it once was, methinks (then was the time when Pokemon was the biggest thing ever).
Also, it'd more than likely wouldn't be on the Wii or the such in 3D. Note that the company who made last gen's and this gen's main 3D games in Colo/XD/PBR was Genius Sonority - yet all of the handheld games were made by Game Freak, who don't do stuff on the Wii. I'd doubt they would suddenly do so, let alone let another company redo a game that they made when they are definately still in business.
Down the track, maybe another remake of RB would be made, and maybe it'd have some aspects of Yellow - who knows? But I find it unlikely, and if it would happen, it would be in the distant future, seeing as they made FR/LG not so long ago. If another remake would happen, the first would most probably be a GS remake, given all of the stuff that suggests it, and that is nowhere near to being confirmed anyway.
