Just as others mentioned, it differs depending on what kind of job you are applying to. I think mine is 2.5 pages (will have to check, have not seen it in a while 
), but I'm a "permie", so as TW mentioned, for me it's more of an "anchor" for the interview. Usually I make minor adjustments for every position to highlight the specific skills.
I would say though that a too detailed resume can have a negative effect as well. For example, once we've interviewed a consultant who (allegedly) had experience with SD and listed what seemed like every single item in SPRO: configured item category, configured order type, etc. I'm kidding you not, it was like 10 pages. But to any experienced SD person this would be very basic stuff (similarly ABAPers usually don't mention "wrote IF... THEN statements, also proficient in ELSE" as an achievement). Unsurprisingly, the interview didn't go very well.
Overall in the SAP world longer CV/resumes are not unusual, but I bet you're losing the majority of readers on page 4 unless your resume tells a great story.