Actually there is one way, though it’s taxed hard. You can buy very expensive item from the market, transfer it to your alt and then sell at a lower price. This way you’ll lose like 40% of the money but eventually transfer it to your character.
Though I’ve posted a suggestion about enabling limited silver transfer (like 10000 at level 1 + 2000*1.01^lvl per level, up to level 200) but restricting AH trading for lower level(below 200) characters instead, so they won’t be able to sell items higher then their level for example.
It will help you to more easier support your alts but prevent them from recieving excessive amounts of money.
Maybe a good idea would be adding Interaccount silver stash from which every character would be able to get capped amount of money.
So before level 200 money you can recieve from stash should be capped by level (so you won’t be able to recieve more money until you levelup), and past level 200 it will be current max cash + 15000/lvl PER MONTH (~2.5m silver per month for every character lvl 280).
This will help a lot, I assume.