Where can I get 1/2 trays for seed starting?

I have been searching for a while to find trays (no holes on the bottem)
to hold seed pots for bottem watering. I used to get 1/2 width ones
(same length ~20" but only 6-7" wide) at Frank's but they went bankrupt.
Any ideas for a new source?

Also - I reuse my trays and would like very sturdy ones (not the flimsy
$1/ea ones you can buy everywhere). I once bought some really nice
ones at A. M. Leonard but they don't seem to sell 'em anymore. Any
suggestions for something along these lines?

Thanks
Tam