I may be one in a hundred who got TRV accepted while PR is in Process
( My application filed date is 27th March 2014) but the main thing is that CIC allows dual intent.If TRV is rejected before u applied for PR then it might affect PR Processing ( there i one column in a form for PR in which they ask if u have been denied visa ever) as they may ask the reason for the same but if u apply for TRV after Spousal application and in worst case it gets rejected then also it is not going to affect the application anyways.
I think u should apply for ur wife's TRV. Just make sure that u show CIC enough reasons that she is going to return India after certain time. As i mentioned already that me and my husband did a lot of homework for that( applying for TRV was no less tedious then applying for PR), try to find the reasons and show as much proof as u can which u can show her connection to India.Leave letter from job, Property Papers(though i did not shows this), Travel history helps a lot..Work for it as u did for PR and apply. May be u become lucky this time !! Instead of missing each other everyday and fighting over the fone
working for TRV may prove to be more fruitful to you. All the best