Am I correct in thinking that I can use a rb493 for bandwidth control similar to an rb1000/rb1100? Or is the bandwidth control dependent on having RouterOS lvl 6?

http://wiki.mikrotik.com/wiki/License_levels

All license levels other than 1 or demo have unlimited queues.

That's what I thought. Just wanted confirmation. Thanks!

only limiting feature is how much bandwidth you have to filter and how complex your configuration is.

As far as bandwidth, I'll be using this to manage a 5 Mb WAN connection (possibly upgraded to 10 Mb). I'm not sure how complex the configuration will be. The connection will be split between 9 separate connections, each with their own firewall.
Is there any sort of way to gauge whether the configuration will be too complex for a rb493?

ETA:
Basically, I think all I'll try do is give priority to the public IPs that belong to my corporate firewalls and give the IPs that belong to the firewalls of my "guest" access lower priority. I'll probably do more traffic shaping on each firewall (so the rb493 will be my "core" router).....

If you have 9 WANs, you need a RB4103 xD

You need 9 connections for each WAN and one for the LAN. Or you can connect various WAN to the same ether.

I'll only need 8 physical ports. Four of the firewall connections will be via redundant wireless bridges.