The AT-HA5000 is now offered by Audiocubes for 1.150 Euros ($1.350), plus the additional costs for the import.
In that pricerange, there would be the RudiStor RPX33 as a strong competor, a double-mono SS-amp, unlike the other Rudis not dedicated to the HD650s that much, but rather unique, and from what I`ve read and seen, probably the ideal solution for an AD2000.
The RPX33 goes for 1.300 Euros.
Now while that would be the heaven of HAs, one should probably try to keep both feet on the ground...
In the pricerange of the Corda Arias there is another RudiStor as a strong competor, for 475 Euros, the NX-01.
Already recommended by cosmophagma, this amp indeed seems to suit the AD2000 almost perfectly, at least from what I`ve read about it.
An interesting review of the RudiStor NX-01 I`ve found here:
http://ipastudio.com/reviews/showpro...hp/product/108
Decisions, decisions...