Yes, there are a number of these here in Canada. I acquired an OVS Mauser earlier this year, thanks to contacts here on CGN, and I'm very pleased to have been able to get an example.
Mine is personalized, to an S.J. Geel whom, thanks to Rob D., I now know was from Leeuwfontein / Lieuwfontein ( = Lion spring) in Boshof district, OVS.
He was captured and deported to a POW camp in Bermuda.
He would have been in the Boshof Commando, which had a very good combat record (Modder River, Magersfontein, Siege of Kimberley). Rob believes, in part because of the significant role Canadian troops played in the battle, that this rifle was probably captured at Cronje's surrender at Paardeberg, 27 Feb 1900.
Many, mine included, are bolt-mismatched, likely a function of a soldier grabbing a rifle from one pile of captured arms, and a bolt from another.
I'd also like to put in a plug (I posted this on a separate thread here) for Dave George and his books. I was recently in communication with him and he's found another 90 or so personalized Anglo-Boer firearms, and is looking for more so he can produce his third volume. The link provided in tacfoley's post will allow you to contact him if you've got a firearm so marked.
They're out there. A WTB ad might just generate a lead or two.