Sure, you can get too many links at once. I don't claim to monitor anyone's link building strategies, you are responsible for knowing how much is too much.
One nice thing abou blog comments is they are most generally held for moderation. So if you do 5000 links and they mostly hit moderation, the 5000 links will show up typically over a 3+ week period. Plus Google doesn't crawl every site every day, so it could be a week or two after that before they hit the engines, so thats spread over potentially a 4-5 week time frame or more.
Secondly getting tons links isn't bad. Engines love viral topics, if you understand the simulation of SEO and you simulate all other areas efficiently you could certainly appear as viral and 5000 links in a couple of days could be a healthly thing. Again, a tool is only as good as its master, and its up to the purchaser to understand what they need and when they need it. I just sell gas, I don't drive your car for you.
I personally have not had any domains penalized for getting too many links too quick. I wouldn't reccommend registering a new site and then turning around and ordering the 12,000 link pack unless you really understand what that is going to do to your site and are prepared to use that to your advantage.
As for slowing things down, I don't necessarily have a set method that would deliver it over time persay. I can, if you like, just work on your project from time to time when I have some free time in between orders or something like that. That would obviously delay reports and that sort of thing, but if you would like that I can do it for you.
Thank you for your answer. I will talk with my JV partner and check first with him but we'll probably order your service.