Those are great youtube video's Mike, thanks for posting!! i have seen them before but always great to watch again. But yes, you are correct a gen 1 cougar would be fantastic and has all the same running gear as a Mustang and as i've stated over on the VCC posting the parts are available via the aftermarket industry, infact a Cougar can be bought for less than haft the price of a Mustang in the USA, my mate Rex in Modesto, CA just sold a mint going driving 67 Cougar for $3800USD, cheap!! they can be set up the same in the handling department as a Mustang. Paul Stacey who is on this forum has a 70 Cougar amost finished for HMC, hopefully we'll see it in the near future, it will certainly add a great flavour to HMC !!
As for building a Gen 1 Cougar, go for it, it can be affordable and something different!!
Dale M