One thing I have been chewing on since I read the recent Cruciani paper on R1b1a-V88 is that, at least in that study, the region where R1b1-P25 has highest basal diversity (by haplogroups) are Italy and West Asia. Both regions have R1b1a, R1b1b and some other R1b1* (3/1173=0.25% in Italy and 1/328=0.3% in West Asia).
Another R1b1* was observed in the East Asian sample but this region lacks R1b1a.
The Italian R1b1* seems to belong (by haplotype) to two different subclades, what makes Italy provisionally a good candidate for the origin of R1b1. However notice that the Italian sample is much larger than the West Asian one, almost in direct proportion to the number of R1b1* individuals found.
Italy (incl. Corsica and Sardinia) also has high R1b1a diversity (by subhaplogroups: 2/4 basal sublineages, but lacks R1b1a*). This would suggest that the origin of R1b1a actually lays towards Africa, where basal diversity seems somewhat higher.
Of course it's a very tricky issue. Take with a grain of salt.