I agree with Bill. Find the property first, then figure out the deal second. I would also check the pride factor a the door--meaning get your co-signer involved and don't worry about it being your Dad or whatever. I am working on a self storage project in Texas and the sponsor is doing the same thing with my company's investment--having us come in as co-signers (effectively) on the debt, to get the deal done. So it is done all the time by the pros as well.
This may be outside the scope, but have you considered picking the neighborhood you wish to live in, rent a property and work on buying that property. I think owners are far more receptive to their cash inflow streams then some flyer which pops up in their mail.
I also think seller financing for your first deal is a long shot. I am not a RE agent, but my experience recently is cash/debt deals are the standard, and seller financings are few and far between. Let me know if I can help also.
