Nope, there is no restriction on post lenght here (unless you keep posting posts that just contains a smiley or one or two words outside the randomness section) and it is also possible to bump your topics if you got a new update after several hours on a project for example, or have another question on something but your topic got dropped off the latest new post list.
The only issues, though, is that if posts are excessively long, people might not bother reading through them, especially if they have trouble reading texts (like me) so it's always good to summarize its content in the first paragraph
, and double-posting for no reason or abusing it is not recommended since we can always reset post count to zero
EDIT (since someone posted): tl;dr means "too long; didn't read.". Another comment on large posts, if they're replies, not new topics, due to high activity over here it's very common that from the time you started replying until you hit Post, some other replies will have been made. Also, sometimes the server/forum software will epic fail and throw you an error when clicking "Post". Always copy your long posts in the clipboard before hitting reply
EDIT: darn this topic is fast