You mention in the first post about doing 5-gal batches and selling those - the problem is, non-sankey systems (read: corny kegs) pretty much don't exist in most pubs/bars, so convincing someone to dedicate time, tap space and equipment costs to not only a brewer just getting off the ground but also to a different tapping system from what they have already, will be difficult.
The other thing about 5-gal vs Sankey is workload - if your beer is really popular, they're going to have to have someone going down to the cold storage and swapping kegs out more often.
If you're going to do sankey kegs, you're going to have to brew basically three times the same batch for one keg, which is three times the work you want to be doing.
My suggestion, if you wanna be serious about this, is to first get your brewhouse up to handling 15.5 gallon batches. Shouldn't cost you too much, and from what I've seen filling sankeys without all that filling machinery isn't terribly difficult.
My $0,02 anyway.