The front magnets came about for exactly the reasons you say, adding bigger rear magnets would just make the car slower or stop altogether, unless more power was used, but the 4-magnet idea might make the car a better balanced one.
You are correct about the car being bulky. It was machined from plastic, made deliberately wide to accomodate lexan bodies & the pickup assembly was somewhat half-assed. But as a first attempt it was not too bad, the one and only time I ran it at a national (in the lunchbreak) it was 0.4s quicker than anything else (the 'proper' cars of course had polycarbonate bodies).
But the pickup assembly worked poorly with H:O rail, the COG was too high as the floor was nearly 1mm thick and there were one or too other issues which the new design will address.
With regard to the motor, I think that it would be too much to design a Tyco-type system when can motors can be dropped in and be plenty fast enough for the UK scene. Of course I would love to sell cars outside my own club mates but I think that the can motor will be the only option for the forseeable.
It is a shame that armatures get ever better but that nobody makes upgraded can motor magnets. I did wonder if the 'T' lifelike motor might be an option as it does have very strong magnets, maybe these could be moved in closer to the arm and the arm itself upgraded.
So maybe I'll make a means to clip these motors in, but there is no way I'd make the car to only accept these unless I found a plentiful cheap supply and my ideas actually worked.
At the moment the pursuit is to see what can be built & how well it runs, selling on is in the background for now. If I do go that route it will probably be just bare chassis into which the customer can drop his own parts, maybe a club could initiate a new class etc.
Maybe enough interest will be generated that some of the ideas end up on the SRT2/Patriot P5/T-cat2 etc.......