Ok, as the ET based rambling went nowhere and some people (especially Steven) had some valid point on the simplicity of the underlying representation, i am about to propose the following plan. The premises still are that I believe that at some point an ET layers is worthwhile. So here it is: 1/ restructure XInt so a generic way to access to the needed internals of the big integer representation through a terse Concept providing way to specify how to store and retirvee bits o. 2/ Build the xinteger_t type on top of this generic layer. Let's stop here. At this point, we fulfill needs expressed by Chad and Steven: a simple and generic large integer library ready to be used. Now this I can see as a very valid candiate to be accepted right now. So now, what's going afterward ? By using the concept and interface, we ( and by we, maybe I mean only me for the moment) can do the following: 3/ implement a EDSL on top of the interface defined in 1/ By reusing the low level memory and computation interface we can build a ET-enabled large integer that behave the same way than the original large integer type in 2/ but allow us to add "fancy" optimisations 4/ Have a way to say large integer use SIMD register of 128 bits and implement a SIMD aware large integer Or any combination of 3+4 or any other similar extension. So, can the effort required by 1/ (definition of a minimal concept for handling representation of large integer) and 2/ seems valid ? I think this actually gives everything to everyone : the simplicity concerned public and the "fancy" public. Of course, the only thing Chad may have to do is 1+2, leaving 3+ to people interested to provide such extension later. How does it sound ?