There are two balanced dacs that I am aware of under $500 but I certainly am no expert at the price range. They are the Matrix mini-i which I have never heard and the Yulong D100. I believe the latter is just about $500 and it is a very good dac but also has an ok amp. I did not have the HD800 at the same time as the D100 but it was a pretty good dac esp at $500. It won't be perfect but a pretty versatile unit in how you want to use it. I think it might be comparable to my concero but it's been a long time since I owned it. Balanced dacs under $500 are not that plentiful unfortunately.
For a balanced DAC under $500, a used PS Audio DLIII is a great option IMO.
For under $2500, the W4S DAC-2 is the best I've heard. For under $5k, I like the Weiss DAC.