This can be done reasonably well with XBee ZBs (S2) in API mode. After a module completes a transmission request, it sends a TX Status frame which indicates success or failure of the transmission.
I think the XBee 802.15.4 (S1) modules operate very similarly, but I've only used this with S2.
Not sure why it's important to you, but for short payloads, I typically see 25-30ms if just a single hop is involved.