I'm about to receive my Smeggy Thunderpants, which will be my very first set of high-end headphones!  Previously I have only owned low-end crud and a couple of mid-range Sennheiser 500 series, which I enjoyed for what they were.  I have little experience with dedicated amps and the like.
 
I mostly listen to FLACs on my PC using Foobar. I enjoy a very wide variety of musical genres, so picking just one or two as examples is impossible.
 
What I have now is a Presonus Firebox, It's nice for what it cost, but it was meant for recording, not for use as a headphone amplifier/DAC.
 
What I'm looking for is a reasonably-priced tube amp that will drive my Thunderpants and a DAC that supports at least 192Khz.  I can deal with buying them separately or purchasing an integrated unit, but I can't spend more than $400 total.
 
I've heard rave reviews of the Cavalli CTH, but I really don't know if I'm up to building one of these myself, and I don't really see them for sale pre-assembled anywhere.  If anyone has any links for me as far as this, please let me know.
 
I've also seen the "Project Sunrise" spoken of highly, and the price on eBay is within my range.  But I'd like a more informed opinion as I know almost nothing about what's out there.
 
As for a DAC or an integrated amp/DAC combo, I really and truly have no idea.  I've combed through these threads but the amount of information is overwhelming, so I'd greatly appreciate some informed input.
 
Like I said: my total budget is $400 (preferably less).  If anyone has any ideas or sees anything for sale I should be interested in, fire away!

C'mon, not a single reply in three days?  Just throw some ideas my way if you've got a second!

Well, there ARE a lot of these questions already answered a gazillion times here on Head-Fi. A short search will lead you to pretty decent answers. Little Dot, Bottlehead, Darkvoice etc... 
 
The Sunrise is actually pretty cool. You can go a long way by just getting an Indeed Bravo tube amp from Ebay and modding it yourself though. That's basically all the Sunrise is really.  

Oh, I see plenty of threads discussing DACs and amps, but I wasn't able to find more than one or two Thunderpants-specific amp discussions in the searches I did prior to creating this thread.  Maybe I'm just bad at searching, but it's not from lack of trying.
 
Anyway, I appreciate the ideas.  I'm leaning towards getting a Sunrise kit for about $185.  I've seen the pics of the kit, and it seems very well put together with clear labels, good parts, and good organization.
 
I still have no idea what I'm gonna do about a DAC if I go that route, though.  Luckily, I can get a lot more out of the generic DAC threads here as the performance of a DAC isn't going to be affected by the specific headphones (Thunderpants, in this case).

How does the Bottlehead Crack OTL compare to the Sunrise?  They're both in the same price range.