There is already one: GrantCoin designed for this exact purpose, and I would say that Steemit definitely borders on the topic too. Between getting a few steem for free when you join, and getting curation rewards just for clicking 10 times a day, that's pretty close to a universal basic income.

Inflation is already part of every currency, whether fiat or crypto. The issue becomes uncontrolled/unstable inflation. With STEEM, that inflation is split between witnesses, curators, and authors, effectively limiting it's effect on the system by spreading it as evenly & widely as possibly.

If a crypto worked on any of the same basic mining/creation/inflation principles as BTC and the like, but say the miners got 25% and the other 75% is split evenly amongst all holders, then you haven't created any more inflation, but you have created a universal income. Just one though, I'm sure there are lots of folks already writing up the code for these things.