I have a sports targeted website. Does anyone know any CPM review sites, or a list of reputable CPM sites. I’ve used Burst and Casale in the past, looking for new options. Reputable and high CPM.
cpx interactive
Casale is good,
Gunggo has a pretty good list for sports
Clicksor is good
ValueClick and Tribal Fusion.
The four top tier networks haven’t really changed in a while to be honest.
Tribal Fusion, Burst Media, Casale Media and Valueclick Media are still the best general ad networks around in my opinion.
As for the sport niche - have you tried affiliate networks? I imagine you could see better eCPMs if the campaigns wee for selling sports clothes/equipment/memorabilia or whatever is relevant to your site. CPA is more work but can pay off very well.
I have tried them all and Valueclick is the killer and it even gets better of the time. Yesterday I had an average of $1.50 CPM. Give them a try 
Strange you did not make any good with Casale and Burst… if you want maximize profit and anoy visitors a bit than use clicksor with popups… And here is what you were asking for… CPM review site: www.pay-per-impression.com
You said you used them in the past, but why don’t you try Casale and Burst again. ValueClick is also another one.
For CPM Advertising Networks and sports, i suggest to try affiliate marketing networks. It helps for buying and selling with sports equipments, clothes and many more.