Well, I see that Doc has not mentioned the Bottlehead R&D plans yet. But they come close to addressing this issue, so I'll put up a few remarks.
The Repro Amp has three stages, as has been noted. The first two stages (EF86 and 6DJ8/6922/7308) have 20dB more gain than the Seduction, and the third stage adds another 12dB plus the ability to drive balanced 600 ohm lines. There is also an unbalanced output after the second stage. Of the 20dB extra gain in the first two stages, 10dB goes to extending the bass flat to 17Hz vs. 50Hz with Seduction for IEC tape equalization, and the other 10dB goes to greater gain for the less sensitive tape heads. Getting this much gain from an EF86 is pretty tricky, and for the best performance you do want to find some prime examples of the EF86.
For some time we have been working to produce a phono (RIAA) preamp kit using just those first two stages. For RIAA applications we'll shoot for only 10dB more gain, since the bass issue is not a problem with RIAA. That gives us more latitude with respect to EF86 selection. Obviously it will be more costly than the Seduction, but less than the full-fledged Repro Preamp. Even when it comes out, it may be some time before we have a tape head modification for it that we are entirely happy with (i.e. incorporating the deeper bass of a full IEC implementation). But we are working to provide a higher-gain option. The first prototype has been evaluated, and the second version is being designed. I can't say when it will be available, because we don't know how many more versions will be needed.