Ok... some suggestions:
1 Warm
I know this one gets tall but I suspect new plants wouldn't be that tall to start with... specimens are pricey but flowering sized plants are ok, canes are 18 in to 2 feet. Dendrobium spectabile
$25 from Oak Hill Gardens
9,90 € from Orchideen Lucke
1 Intermediate
Dendrochilium wenzellii
Oak Hill Gardens for $14
Another intermediate:
I'm seconding the suggestion of Maxilaria tenufolia... I"ve been entranced by them for awhile now and this would be a good chance to try one out.
Yet another intermediate:
Zygopetalum maculatum (because I can't get enough of Zygos!!)
At Andy's Orchids for $20