Do you want the standards to be ivory? Or a deep rose or maroon self?

The most velvety maroon I've seen is Robe of Royalty. It opens a deep sootish reddish maroon color and the standards lighten to a subdued deep maroon with the falls darker with gorgeous velvetness. Oh heck. I've got a picture that's quite accurate colorwise. I don't think I've seen the velvet in any of the medium tones. Only purples and this one.

Robe of Royalty - falls really are velvety

Robe of Royalty is beautiful.
Have a look at 'Wearing Rubies':
http://wiki.irises.org/bin/view/TbUthruZ/TbWearingRubies

'Beauty School' might be just what you're looking for. It's a newer introduction from Australian hybridizer, Barry Blyth.

http://wiki.irises.org/bin/view/TbAthruE/TbBeautySchool