With regards to financial institutions ordering bricks, I believe they can only order them in crisp bills when that particular bank accumulates 1,000 bills of the same denomination that are deemed unfit for circulation. That probably explains why the Scotiabank branch in my neighbourhood (which is a small branch) doesn't go through the cycle of $10 bills as fast as a branch located in a busy shopping mall that serves numerous commercial customers on a daily basis. I'm lucky to be getting crisp $5's more often at the branch across the street from where I live. In fact, I got some crisp APG's just recently, and the day before I got some crisp $10 BTK's at a CIBC branch (which is located in a very busy shopping mall). I wouldn't be one bit surprised if some Scotiabank branches do not order $10 bills on a regular basis.
But back on topic with the $5 bricks, yes, you can get bundles of 100 - but only if you request them from the teller over the counter. You would probably have to do a cash exchange if anything at all. Tellers only have so many $5 bills to disperse in the run of a day, and if they gave 100 of such denomination to one customer and did that to numerous customers, their supply for that week would sink faster than the Titanic. In other words, there would be a significant drought of $5's for a prolonged period (and the local Scotiabank I deal with experienced an "abnormal" drought of $10's prior to Christmas 2005), and the last thing a teller wants to do is end up distributing large quantities of loonies and toonies to numerous customers (Imagine if the teller had no $10's and $5's - such occurrence happens extremely rarely).
But for the most part, as much as tellers want to give anyone 100 crisp $5's, they probably have regulations to follow and they have to distribute them sparingly. $5 bills are, I believe, considered a more vital denomination (as are $20's) than $10's, $50's, and $100's. A bank only receives the $5's in limited quantities of crisp, you know. And no, I never did request for 100 $5 bills in my entire life. The largest quantity of $5's I would request from a bank teller would be no greater than 20. The "first come, first served" rule at many banks usually applies to larger denominations, but I can see why it doesn't apply to smaller denominations.