Elipsos Overnight Train Reservations

Unfortunately, it is very difficult if not impossible to get reservations only over the web. RailEurope might be your best option, but their first class double sleeper, at a $344 supplement ON TOP of using a railpass day, is almost as expensive as purchasing the sleeper ticket on the web...it's 255 Euro, or about $370. Advance purchases on the web can be as low as 120 Euro pp ($170) for the same sleeper, when travelling as a couple.
Elipsos currently has not published fares or schedules for the high season beyond 5 April...that's probably why they're not available at RailEurope yet.
I THINK you might be able to book reservations at a more reasonable rate by calling the German national rail service...I hope one of our German rail experts can confirm that.
You might also want to try calling the RENFE agent's office in London, where English-speakers will be present. Click here for their website. They might be able to have the reservations available for pickup in Barcelona.
However, you won't find any site where you can get reservations only, and print them out at home. Few people get railpasses these days, because it's much more economical to check the various national rail websites and purchase tickets point to point....that's where you get the ability to print at home.

A third option might be to consider submitting a fare request to the Swiss national rail network, SBB, since your journey ends in Switzerland. Their website allows you to submit a request for reservations only....they'll get back to you by e-mail for a quote. Make sure you submit for two people, because the sleeping compartments are segregated by gender unless you reserve both bunks.

I second the "Swiss option" listed above.

Keep in mind, reservations for Spanish "trenhotel" service are quite expensive in country, even with the pass! They'll be outrageously expensive on RailEurope.

It's a dirty little secret they don't tell you when they sell rail passes, but it is difficult to get reservations (except on CNL) online unless you get them through either RailEurope (at higher than European prices) or from Euraide at the European price but with a $50 shipping and handling charge.

German Rail can sell you reservations, just not online. You can call them at (49) 1805 99 66 33.

It looks like trying to get a reservation on any of the websites are out. I'll have to cave and pick up the phone to call around. I was trying to avoid that!

I'll give RENFE's London office a call, and if not there, the German rail line. I saw the info for Euraide somewhere else on Rick's site, so maybe use them as a last resort.

Thanks for all the help! This place has been such a great resource.