What do you guys think about using blog rolls get get a large number of links in a short period of time?
I think you'd be better off just focusing on homepage or subpage links. Run of the site links tend to get discounted as it's pretty apparent that they're not natural.
Your answers is pretty much included in your question. Anything large in number in a short time is suspicious in SEO (and for Google). Give everything a break and try variety of things to learn and explore results.
Blog rools are great link, it is a side wide link that give you more backlinks than any other single page links. The best are those that come from related blogs
It's a waste of time/money. Focus on Quality not Quantity. 10 Quality links are better than 200 site-wide blog roll links from one site. Surely you didn't think it was this easy to Game the Search Results. haha