Try a Main-Gauche/Parrying Dagger.
A parrying dagger is a traditional companion for any rapier, and would be so beautiful to have along with an Agrippa (Which I have, for instance!) or a sabre. Especially if you make a closed or ringleted crossguard such as in http://www.kultofathena.com/images%5CDSA1807BK_5_l.jpg , it would be a perfect weapon!
This idea is already in the making! We’ve started designing it, but it’ll take a while before it’s out! :-)
Ilan Inglis commented
any advancement on this one? I just handled one of your swords for the firs time, and after seeing it authorised for the local game system, I have no more excuses not to get some of your fine arms. :)
this would be great with a Rapier.
Sean Burnett commented
The Main Gaunche should be built as a companion dagger to the Aggripa which really is your main rapier. So the parrying dagger should borrow aspects from it. So one that goes with Agrippa would have to be compatible with Agrippa. One that would fit Aggripa in my opinion would be like this. http://www.kaswords.com/ProductImages/swords_and_displays/medieval_swords/M5911-02.jpg. Also the Agrippa swor is 42 inches long so the dagger could be anywhere from flat half (21 inches) to around 17 inches. The colour scheme should be the same as Aggripa.