Hi,
Yes, it is possible. Actually last night I submitted my visit visa application. I will take the Canadian Registered Nurse Examination on October 6, 2010. I have a pending PR application,which is in process since July 31, 2010. Until now I am still waiting for my medicals. Just ensure that you will fill the PR application information on the designated space in the visit visa application form.
Tourist visa applicants with pending PR application will face a huge challenge to convince the VO to issue you the visit visa. Chances are lesser compared to those who do not have pending PR applications. You got to have some strong reasons for the visit and strong ties back home to give the VO the impression that you will leave Canada after your visit. In my case, I have the letter from the regulating body (College of Registered Nurse of Manitoba) addressed to the VO, stating the reason why I need to be issued with the visit visa. I will not be travelling with my family on my visit to Canada. I gave them as well some documents that I am currently employed, approved vacation leave from the HR department of my employer, and round trip ticket.
I will give you an update after around 21 days, if I got the visa or not.