Topband: Beverage ground rod substitute

[Thomas]

All of this talk about a short Beverage antenna has me thinking I just might be able to install one 250-280' E-W wire. One issue would be the ground rod. The earth here  is Caliche which is quite similar in properties to concrete, so I can't drive a ground rod into it. I've thought about using short buried radials like I do with my K9AY, but the Beverage termination points will be in the extreme corners of my lot.

Any ideas what could be substituted and might work as well as the simple ground rod earth? It is funny I find myself attempting to make the proverbial silk purse from the sow's ear! 

Tnx, Thomas - AC7A (Tucson)