Having been on the other side of the situation, here's my experience:
Phones ring non-stop all day and emails never stop coming in -- all because one asshole vendor/sales guy put your contact details into Salesforce or something similar, and there's a global data pool. For a little over a year, SalesForce thought I was the CTO of IAC -- all of it -- not one of their holdings. The amount of phone and email spam I got was ludicrous. Sometimes a caller is able to get trick their way past admin assistants - they immediately go on your black list. Sometimes a caller gets your direct contact details, suddenly you have a voice mail every 24-72 hours of them trying to get through - they get to the top of your black list. You amass a huge array of phone numbers , email addresses and products that you never want to use -- ever. You don't know who they are, what they do, or how much they cost. All you care about is that they have an aggressive sales force who claims that they want to help you - yet makes your day as nightmarish as possible. Even cold email pitches are annoying - you get at least 10 of them a day. You don't want to read them, but if you did... you don't have time.
So who gets their calls answered , emails read, or a chance to pitch you ?
Introductions from friends , industry contacts and former colleagues will at least get a paragraph or two read. 9/10 times that will lead to a phone call. If the idea is actually useful, a portion of those will get a face-to-face. If you don't have a connection to the 'decision maker', see if you have one to someone in their office. Staff always wants to look good. If a trusted engineer or product manager came to me and said "this is a friend of a friend's company , it looks useful and not like a total waste of your time," then we looked at the product together and decided if it was interesting enough to warrant further action. Even if I thought it was crap, if my team members really believed in it, we'd schedule a call or meeting.
Bottom line: any sort of "qualified lead" from a lead-gen professional is going to be hard to get for you, and start out a bit tenuous. If your team and advisors can't make a phonecall to get you in to pitch someone , or your current clients/customers won't push you into their network - you've got a larger problem than lead-gen.
Pre-beta sales and IT sales are both completely different beasts. The vast majority of pre-beta sales I've seen have been either :
1. Startup has some sort of pull at a company. Their college roommate is the decision maker, or they used to be in the top staff. The sale isn't done on any merits, its a courtesy.
2. The product is coming from an existing company , and you're getting a serious discount for pre-ordering or test-driving as a "launch partner". it usually comes with a 3-9 month free trial.
3. The product is a new feature from an existing vendor. you're getting a pre-launch discount if you commit to something.
Dealing with Corporate IT is a completely different beast. The word "beta" throws them off in a heartbeat.
+1 to Rahul's Customer Development strategy. All the startups my corp team engaged needed a lot of hand-holding to fine-tune their product and pitch to something usable. A lot of people came in with an interesting piece of technology, but had no idea how the corps run from the inside or how our technology stacks were implemented. We helped some understand products that we'd actually consider buying, and would intro to our network if we liked the idea or team.
+1 to Michael's comment.
I'd also add that the first thing we would ask someone is "who is your largest customer so far" , usually followed by financial questions. good answers were "X uses us" or "not live yet, but we developed this with x,y,z". It's a HUGE turn off when someone is trying to sell us something that hasn't been sold before, wasn't customer developed with someone else, and hasn't gone through a free trial.