I am assuming you are talking about a frost tender Pelargonium.
There are a few dark red pellies on the market, if you like this particular colour group look out for; Tom Cat/Boy; Merlot and Blackmagic. There is also a beautiful Regal Pelargonium 'Lord Bute'.
I think that Tom Cat and Tomboy are the same variety. I have not tried to root any of the pellies yet but I hope to do so in the autumn. One problem I have encountered with other trailing pellies is the long internodal lenghth and this can make it difficult to find good cutting material. Try using an ascorbic acid dip NOT rooting hormone and do not tent your cuttings.

Black magic, try the test gallery to work out how to post your photo, then post it in the gallery here.