2001 - Battery replacement options?

I have a 1st gen Prius that I bought new in 2000. I have 140k miles on it, and last weekend, the warning lights came on. I brought it in to the dealer and they tell me the hybrid battery needs to be replaced for a price of $3200, and also the ECU may need to be replaced as well for an additional $1300. I've been expecting the battery replacement for some time now, and the ECU is just an added inconvenience. I talked to an automotive repair shop that said they would work with me on the price if I was willing to be be a guinea pig for other more innovative replacement options. (The mechanic also owns a Prius). So I was just wondering what other options are out there besides the standard Toyota replacement battery. Any input on the matter would be appreciated.

 

Didn't specify, but said I should check on this site. I also just found someone on Craigslist who claims to be able to switch out the old battery with a reconditioned one for half the price of the dealer price for a new one. His process sounds like what Re-Involt describes on their website. Craigslist... wish me luck.