is there a limit to how many shsh blobs cydia will store for you? because i have 2 iphone 3g[s] old bootrom and one has shs blobs for 3.1, 3.1.2, 3.1.3, 4.0, and 4.0.1 and the other one has shsh blobs for 4.0, 4.0.1, 4.0.2 and 4.1
No limit, it is either a bug or cydia hasn't got around to doing the latest ones yet for you. I suggest use tiny umbrella to save them yourself and force cydia to save them for 4.1 just in case.
Cydia is currently still saving and logging the blobs for iOS 4.1.
As far as 4.0.2 is concerned, I believe it was a combination of Apple just not signing it long enough and Cydia not being updated to grab the 4.0.2 blobs fast enough to get all users blobs on file.
If your update caused you to lost cydia then you are no longer jailbroken.
Please do not post random requests in unrelated threads. If this is such a concern for you, then you may post a thread in one of the appropriate forums asking for help.