But your initial statement was about the lack of high end/lightweight square taper cranks.
I could do all sorts of things. But what I want is a decent reliable square taper set up, to replace the unreliable crap external BB set ups I currently have. Thanks for your advice though, appreciated.
Taking Middleburn cranks as an example you'll spend more than XT for something that weighs more than Deore with questionable reliability.
I know a few folk who've used/still use Middleburn stuff, and it appears to be pretty reliable. I'm willing to sacrifice a bit of weight for increased longevity and reliability.