There is a Primare CD21 listed on Agon now. That could solve your problem if you are happy with the Arcam.
As to the original question though, I'm a bit confused. You say you want to stay with your cdp's dac, well using the digital input on an integrated won't accomplish this. You'll be using the integrated amp's dac. You don't say what Theta model you are using. It may be better than what you'll find in an integrated for $1500.
As to the original question though, I'm a bit confused. You say you want to stay with your cdp's dac, well using the digital input on an integrated won't accomplish this. You'll be using the integrated amp's dac. You don't say what Theta model you are using. It may be better than what you'll find in an integrated for $1500.