Hi there,
I've been struggling to find a method to loadbalance 5x 50/5Mbps WANs whilst using RB's (at the moment using RB1100ahx2).
Not only that but I need a suitable QoS system which will work with the above.

The system will have around 60-65 users attached by a router (something like a SOHO MK or Ubnt Airrouter). So I believe using something like PPPoA/PPPoE + MAC to control access to the network using radius manager 3 (DMA soft labs).
I will be using internal IP's for the whole network and need to employ client separation to prevent snooping.

Basically I need some help, with the hardware to try and minimise the equipment needed. So could someone recommend suitable RB's or say if i need x86 system to run this.
If you can think of a better method of setting up the network to allow more efficient usage of CPU power please let me know.

Your drawing looks good. I wouldn't see why that wouldn't work.

Well, its not so much the drawing issue its the hardware. At the moment I'm running a hotspot on load balancing across 3 WANS and with 2 users CPU usage is at 50%.
I've never actually used PPPoE/PPPoA so but i assume the overheads are much less than a hotspot. But I really need some input from someone whom is running a similar system (i.e. WAN load balancing).

Also another item i'm not sure about is how to really ensure QoS across the WANS, per user. I know there are various methods of QoS setup's but I'd like to hear on some which come under heavy load for its users.

Typically across my existing hotspots I see around 1TB a month transferred (5Mb per user, with 30Mb burst for 30 seconds); but on this network I plan to upsell the broadband and offer each user 25Mb package.