The bad news is, yes, the V3 is discontinued.
The good news is that the V3 was (is) one of the more popular and widely-distributed amps out there and is not at all rare on the used market.
I suppose it's possible that there are dealers out there who still have some "new" inventory. I would start by contacting
Upscale Audio. They are a very large dealer who frequently have used/demo/show pieces available and are probably one of the largest MF dealers in the country; if they don't have one in stock, they might be able to locate one for you.
From what I have read, the V8 has very similar sound quality to the V3. Personally I would prefer (and own) the V3, mainly because the V8 is more expensive, has the USB DAC (I don't stream from a computer, and if I did, I would use a good outboard DAC anyway), and just looks frumpy (IMO). If you found a sweet deal on a V8, you probably cannot go wrong though.
If I were in your position, I would first call Upscale Audio. If they cannot help, then I would just try to be patient and keep an eye out for a good one (at a good price) on the used market. It's a great amp and works very well with all cans I have tried on it (HD650, DT-770 (80 omega), DT-150, HD280, and AH-D 700); I don't think you can go wrong!