Some good suggestions, but I think we are getting away from one of the core pieces of what we originally passed. Each project has an exact RP cost; you must invest that number of RP every turn until the project is finished. You cannot invest more; you may be able to invest less (you can't in HoI, but we determined that it does not necessarily make things much less complicated to have a mechanism through which you could invest, say, half the RP required rather than having sliders and allocations).
It is entirely possible to speed up certain categories (or certain applications within categories, or whatever we like) - however, we can't do this through any sort of allocation mechanism (like splitting up your total RP pool in a particular way).
Once you've invested the RPs, you've lost them until you've researced the project or stopped the project; the thing we can adjust is how long the project takes, or the number of RPs required -- not the number of RPs you are able to allocate to it.
Aquitaine, could you describe a little more about how this will work. What it seems like you're saying is that you support a mechanism to vary the amount of time the project will take but you dont support an allocation mechanism. How can we allow the user to vary the amount of time a particular project takes without allocating something?
Are you suggesting we have three buttons 'half cost' 'full cost' and 'double cost' by which you invest a certain amount to get the project in a certain time? This isn't much different from an allocation mechanism IMO, it just sets (arbitrary) limits on what spending levels you can have.
Or do you intend that the user should have no control over the amount of time, that it is a fixed function of the tech being researched, the previous techs researched, racial and building bonuses, etc?
In either case, I have a concern. I think there should be a method to automatically start new projects in a given field whenever one completes, and let the user override these decisions if they want to. Either that, or we should bring up the research screen with a popup every time a project completes so you can pick something else. The reason is that in a large game with lots of sitrep events to parse, a person could easily forget to start their next research project and not realize it for several turns. It could turn into an annoying micromanagement problem if we aren't careful. The default behavior should be that your empire is always researching something, and you can leave it alone for a while, confident that your scientists will be doing something useful. You should only need to intervene if you have a particular agenda.
EDIT: Given the above, it would be a good idea to have a 'set priorities' mechanism like in SMAC, to control which projects your empire picked next.