With Wesabe announcing they're shutting down a couple days ago, this could be good timing. I'd been using Wesabe for our business accounts (Mint wouldn't work with one of our accounts, and Wesabe's downloader thingy did work, so it won by default). And, if it happens to address business needs a bit better than Mint or Wesabe, that's even better.

It's a huge market, but I think you've got an uphill battle. Quickbooks is so entrenched...I tried really hard to avoid it, but it does damned near everything, every accountant knows it, every tax preparer knows it, every bank exports for it, and it's cheap compared to all of the existing online double-entry products ($100 per year vs. insanely expensive monthly rates for everything I could find; I'm still using the 2009 edition so technically it's getting cheaper by the day). In the past, I didn't have a Windows box handy (Linux is my primary desktop/laptop OS and has been for a dozen years), and so I went to great lengths to deal with alternatives, like running my own SQL Ledger installation. But, now that I have a Windows partition on both machines, Quickbooks isn't a hardship.

But, given that Quickbooks requires me to babysit the transaction imports, and I only do that once every couple of months, having an automatic snapshot of all of our accounts would be awesome.