Hi Pelo,
Parasound Halo A21 (250wpc into 8ohm) has plenty of power for 1038 Be. Unless you listen to music at ear-bleeding level, the amp will stay in class A most of the time. Besides, it doesn't necessarily mean going out of class A and into class A/B is bad. Far from it.
XA60.5 is mono block, which means you will need 2 of them to drive each of your 1038 Be. IMHO XA30.5 (stereo, not mono) is plenty good enough for 1038 Be. Don't be fooled by it's 30 watts class A rating. Stereophile measurement shows it can go up to 130wpc into 8ohm in class A/B before clipping (THD > 0.1%). Besides, watts power rating is only half the story of an amp's ability. Many people has experience XA30.5 driving difficult loads due to its current output. Your 1038 Be is definitely NOT considered difficult load at all.
Again, like I said, X250.5 should be a great choice as well if your budget allows it. You only said $8k budget for ALL of your electronics. In that case, I would not go with X250.5, only because it'd only leave you with $2k for the rest of your needs (preamp + dac + transport + cables + reclocker).
I'm not familiar with Modwright or NAD. But Modwright seems to be a good company with quality products. You probably cannot go wrong with it. Only thing is just to make sure you get HT by-pass (to integrate either AVR or processor for your HT) with the integrated amp you purchase.
From your list, either of MBL, Modwright or Luxman could work. MBl7006 is their entry-level integrated. But I do not know if they have HT by-pass. I personally would not go for Simaudio, I heard their amp/cdp before and not my cup of tea.
I strongly suggest you talk to a Parasound dealer if you want to stay within $8k budget for your whole system. Do not underestimate amp/pre-amp matching. If you aren't experienced, it is better to get same brand for amp and preamp.