At this end - the chain stores seem to get their bulk supplies of pot plants in time for 'special occasions'. Valentine's Day is coming up - it might be worth looking then. Otherwise I'd check with a good garden centre that has an active and imaginative house plants section.

If you know which growers supply to the stores you could maybe ring them and ask. (They'll probably tell you they don't sell to the public - but they should be able to say when that line will be available.)

And, if all else fails - a request on one of the plant exchange sites??

Check around during spring when stores start bringing in new plants. I normally start seeing these things around that time of the year (April, May, June).