The only reason I have g5.3 12 volt spots in my bathroom is I am lazy and have not wanted to fill the holes which will be left after removing the pods, they were MR16 but I suppose since the LED version does not have a multi facilitated reflector and has cooling fins so does not cover the 16/8" they are not MR16 lamps?
I suppose like with the IBM PC because PC was a registered trade mark other makes were called PC compatibles we should call the LED lamps MR16 compatibles, however like the PC or any other name I am sure we will drop the compatible and shorten the name to MR16.
I am not sure about the idea of having a toroidal lighting transformer stuck in the loft space, rated 200 VA I will guess it is using more power than if I used 230 volt GU10 lamps, however not sure about fitting GU10 holders in the pods as the coaxial sockets they plug into may not be rated for 230 volt, plus all the cable would need changing to cable with an earth.
Some people with have electronic transformers which will not give out 50 Hz which the MR16 compatibles have written on their side, but at
£17.04 each for a 50W I would think swapping the transformer to toroidal is likely the best way to deal with old MR16 12 volt lamps to allow conversion to LED.
In the old days having all the bulbs with same fitting was an advantage, however with LED they last so long I no longer stock spares, I have to date not replaced any LED lamps except for some 0.58W ones from Pound World which I assume were faulty from day one. At 50W one transformer would power quite a few LED lamps. OK unlike the 200 VA version it does not have 4 sets of terminals but 12 volt at 4 amp any junction block would do.