Yes spamming may invite penalty. I build about 50 backlinks a day sometimes. at the beginning. now I do a few every week.
i think you won't get penalized because, think that you are starting a website with huge investment and advertising your website in adwords, ypn, adbrite, adcenter and much more for huge $$$$$$$. if you do this you will start getting 1000++ backlinks from starting. do google ban the site?????????? they won't