Paul:
Why not adapt the OFFLINE methods to your site?
One of my clients offers "Partnership Opportunities" to those they think may want to "sponsor" (display ads) the things my client does.
Why not do the same? Offer "Partnership Opportunities" (the ability to display an ad on your site) for an
exclusive period of time and for a
fixed amount of money.
Instead of 3 cents per click - which sees you only making money if someone clicks - charge $X per month, fixed.
If you don't feel like 'pounding the pavement' to get your sponsor/partner,
use leverage and have a commission-only salesman do it.
Michael Ross.
Learn How To Use Leverage In Your Business