Sponsorship seems like the best option for continuing to scale up. Working with larger sponsors rather than multiple smaller ones would be easier to manage.
One consideration, although I'm sure that it's not what you're looking to do, would be to scale down and make pttrns.com a paid only resource, with member paying $5 a month or something similar.
With 1.5m pageviews you could easily monetise the site assuming a $1.50 CPM and unlimited inventory to fill on the advertisers part. If you want a designer-y ad network, then I recommend The Deck. http://decknetwork.net/
Sponsorship seems like the best option for continuing to scale up. Working with larger sponsors rather than multiple smaller ones would be easier to manage.
One consideration, although I'm sure that it's not what you're looking to do, would be to scale down and make pttrns.com a paid only resource, with member paying $5 a month or something similar.
With 1.5m pageviews you could easily monetise the site assuming a $1.50 CPM and unlimited inventory to fill on the advertisers part. If you want a designer-y ad network, then I recommend The Deck. http://decknetwork.net/