Could you not make possibly one of the most significant bounties to the current cryptocoin ecosystem to help deal with this? And that is a bounty for say one of the following scenarios:
1) Implementation and tested patch to dvc which upgrades the system to a full ledger system complete with empty address pruning etc.
2) Hybrid Implementation where 1 or more ledger check points are auto-generated periodically which allow the pruning of the block chain older than the last maintained ledger check point (kind of like a dynamic genesis block of sorts) and all "current" transactions/blocks are processed as normal until they have sufficiently aged and rolled up into the ledger checkpoint system.
3) Some other well discussed/planned and approved idea that meets the same purpose and requirements.
..
Requests have already been made to the bitcoin developers to fix the blockchain bloat problem, no one has done it because it is a very difficult problem. I'd estimate it would take at least a 2,000 BTC bounty to fix the problem. Devcoin currently has a market cap of about 4,000 BTC bitcoins, and realistically can only put 1% to any single bounty, so a maximum 40 BTC bounty. This is way too low to pay for a fix to the bloat problem, so there's no point in offering such a bounty.