last winter i bought a couple of the soil block makers (3/4" and 2" sizes) for starting seeds indoors ,and they're Great for that. but the mini blocker i found was pretty good for seed
ballscubes as well.
i was invited to do a seedball demo at a music festival this summer, it had rained a lot the day before and i had not brought any dry ingredients(duh!).. so we found an area with clay soil, mixed in a lil topsoil,water and a bunch of clover and wildflower seeds then punched out batches of cubes with my soil blocker(was doing a demo of hose too) ,which makes twenty 3/4" cubes per batch, taking a leisurely 5-10 seconds per batch, so 60-120 cubes a minute, in 20 minutes we had well over a thousand .
being small and flat topped and a hot sunny day these lil cubes were plenty dry by sundown. everyone took home a 'batch'.
maybe its not as fun and messy as handrolling clay balls,(we did have to mix the seeds/water ) but if your goal is to make a large amount of uniform "seedballs" quickly, this is a pretty decent method i think !
the mini-20 sells for about $25 + shipping, the 2" cuber is $30 i think. (theres a 5" for like $125+, i just made that one from wood myself)
can be found at
Johnny's select seeds and at pottingblocks.com
if you've never seen them here is a picture
video
http://www.youtube.com/watch?v=x-VMneNrm_4