I did it and do not recommend it. Mainly because it is difficult to maintain all private and instrument knowledge and PTS requirements to pass the final test during the length of training. It is a combined oral and practical.
No guidelines from the FAA for the test so it was difficult to find a local DPE - they were very reluctant to go through all the effort to research, plan and have it blessed. Finally gave up and asked the FSDO. They agreed. The oral was about 5-6 hours and the practical was probably about the same including discussion of the cross country plan, reviewing aircraft logbooks, preflight, and 3.3 hours on the hobbs.
FAA was very thorough and very fair, and I am grateful they volunteered - couldn't have asked for better examiners.
Although it sounds like a good idea to combine, I think it ended up taking more time and money than if they were done separately (not counting the 50 hours xc which was not required).
Afterwards I also saw a lot of benefit in the requirement and experience gained in the 50 hours of cross-country too.
And definitely make sure you can pass the medical before investing a lot of money.
Good luck, whichever path you choose.