join link building networks like Adsy.com and LinksManagement.com and check their inventories. Sometimes, you can see the stats and URLs of their partners and you can figure out who's a "small blogger" by those...
Alternatively, you could join sites like Infolinks.com and BuySellAds.com as an advertiser and check their inventory of publishers and this - again - will allow you to figure out who is a small blogger by checking their stats (number of indexed pages, volume of traffic, asking prices, etc). Sites like Infolinks.com / Advertise.com might ask you to deposit money first before accessing their network, though so beware!