I think you mean equipment, not just gold, right?
I've just finished work on a system to figure out what equipment (mostly magic items) a high level PC should have. Unfortunately, it incorporates my own house rules, so it probably wouldn't be useful for you.
However, if you want to create your own, it's fairly easy to do. I usually start with the assumption that a character's biggest item will be worth 30% or less of his total gold and that item will usually be a weapon or other offensive item. I then spend about 60% of the remaining cash on defensive and mobility based items and spend the remaining 10% on miscellaneous items, often something to boost an important skill. If the character has enough gold, I might replace a major defensive item with a stat booster.
Balsamic Dragon