there are non-DBS sats with Ka capacity , whether they use it or not i dont know . more likely for goverment or highly professional applications. the new hispasat 1E at 30W is suppose to have some Ka capacity for instance. But in any case more likely 28" will probably be small specially if they use highly advanced modulation schemes like 8PSK or above (16APSK and 32APSK are also part of the DVB-S2 standard).
To the OP , what is the brand name of the Ka dish BTW?. Maybe it can shed some light on this topic.