It is possible to do so, however that requires merging them wich in turn requires alot of work. You can't load two mods at once, but you can put their content in the same mod. It is ahrd and from what I know prone to buggs, unless the two mods touch totally different areas. For instance, merging a graphic-enhancement mod and a event-improvement mod most likely won't be a problem since they don't share folders and txt-files. However, if you would merge say RIMP and one of the work-in-progress mods such as Rome Reborn their data would clash and there's a huge risk that the mod won't even be able to load at all.