They've said before this is unlikely
A shame, because where I am, DSL represents >90% of last-mile installs and two boxes is not an adequate solution.
with the ADSL gear I'm pretty sure it has to be locked and compliant for each region, so they would possibly have to have multiple revisions of one board to distribute.
You must be thinking of 5GHz where the FCC wants this stuff to be hardware locked, ie separate SKUs for the USA.
Personally I use TP-Link 8817's, they come pre-bridged and are quite small and cheap.
If TP-Link can kick out DSL CPE on the cheap, then anyone can. The only 'regions' that DSL has I'm aware of are Annex A [over POTS] and Annex B [over ISDN].
The other option to keep costs down is to build an interface style system where 'addon cards' can be made to fit, either directly by Mikrotik or by 3rd parties (think SFP).
It would be great if someone could get a DSL PHY into an SFP module.
Cisco do this and works well being able to add HWIC's etc for different types, means they can build single router, and only manufacture different cards, but this is still a HUGE step to take.
IME a Cisco DSL WIC on its own costs more than an 800-series router with DSL built in! Juniper and Sonicwall's DSL cards are similarly expensive.