I am in what is often mistaken for a professional sorority and an honor fraternity during my undergrad days (& still contribute to both, ehem)
I'm not sure if what I have to offer is much different from anything already said and admittedly, SAI as I experienced it, operates as close to an NPC as possible without actually being an NPC.
Alpha Kappa Psi is a business fraternity, correct? Are there any other business fraternities on your campus? We had Phi Mu Alpha, Mu Phi Epsilon, and Sigma Alpha Iota and because of the multiple orgs, our HQ required us to form a Music Inter-Fraternity Council which included the President & VPM of each org who met monthly to plan events, discuss issues, etc. At my school, MIFC recruitment was structured much like NPC recruitment & took place a couple weeks after NPC recruitment. It took place over a week, usually 4 days. On day one, it was a "Meet the Members" night with groups from all music orgs meeting the PNMs all together in the same room. We always ordered in pizza, socialized, and played icebreakers. Nights 2 & 3 were individual nights that the chapters themed and planned themselves. BUT, in order to eligible to pledge any organization, a PNM had to attend events for all the orgs they were eligible for. Women had to attend MPhiE & SAI and men had to attend MPhiE & Phi Mu Alpha. This made PNMs that were sure they wanted one group go meet the other and possibly change their mind. Now, I don't know how the other two orgs did it, but in SAI, after night 3 we voted and gave out invites to the event, called Formal Rush, which is pretty much NPC pref night. We do a pretty ceremony for the girls to display sisterhood and at the end of the ceremony we delivered bids.
Could you do something like this if there are other business orgs at your school? It works really well for us and we have actually had some girls change their mind about being SAI or MPhiE because of the way we do it. It keeps the girls/guys from being completely close minded.
Phi Sig was done completely differently because we don't have any kind of umbrella organization to operate under. We usually had two weeks of recruitment events. Some were business casual and others were casual. The final event was interview night, the most important night. After that night is when MS took place and people were invited to pledge.
But, in both my orgs, we always had info tables in the Student Center, always had a booth at the "Student Org Preview Day", and nominated ourselves for campus awards because then we would be featured in the student newspaper, get a plaque, etc. Something else the I found to be enterprisingly effective was dragging along that reluctant friend that had no intention of pledging anything. I saw this happen in both my orgs and they went on to become the most dedicated members. Also, having brotherhood events were non-member can come as guests--it lets people see the relationship of the members and makes them want to join.