One problem with RouterOS is that it is actually more expensive than a conventional router when it comes to needing sync ports.
A major way to fix this would be to support cheaper sync cards, such as the Tahoe 932 PCI Board which is only $305 for 2 ports http://www.tahoe-group.com/tahoe_93x.php
It has Linux drivers so I think it should be easy to add.
The other cards supported by RouterOS all seem to be over $800.
We used to support the MOXA PCI101 and it was $299 or $349. They has stopped production of this card. We will be adding support for another card in the next eight weeks that is around this price.
RouterOS has support for LMC / SBE cards.
I can hook you up to some (Limited) cards for under $100.00
These are used cards but the vendor will stand behind them..
They are LMC / SBE 1200P 1T1 PCI cards. (CSU/DSU on card)