I am finding it difficult to find older males models 45 years old and older where I live in Barcelona, Spain. However, every day when I walk down the street I am constantly seeing men of that age who I think would be great to test with.

What would I need to approach people so that they think that it is ligitimate. Is a card with a photo and my name/email enough, or should I make a flyer with a bunch of photos?

The kind of men I am talking about are usually buisnessmen, have jobs, dress well, and look like the photos included. These kind of people dont´usually think of themselves as models, in my experience.

(these guys are models, from ford and scoop... but you know what I mean)
http://tinyurl.com/8y69fbg
http://tinyurl.com/7ndgtkm
http://tinyurl.com/7fxyduw

Hire from a commercial print agency.

Go see Traffic Models. They are located close to the Urquinaona subway stop and should be able to cater to your needs.

You have got to speak up and approach people that you find interesting. It may be awkward but gets easier over time.  Have a business card and after all you are flattering them and guys that age dont hear so many compliments- say like an 18yo girl.  Have a card and say something like:

Hi (hola), I am a photographer and I like to shoot with interesting looking people that I meet in public- would you take my card and consider letting me take your portrait?  It won't cost you anything, it will take 2 hours of your time and I will email you some photos that you may like to use on your FB page or web site or give to your wife.

Then when you send them the pics put your water mark on them so they serve as advertizing .

Be prepared to over come their hesitance- ask if they ever acted? or modeled? If they want they can bring their child along to have a photo taken or wife.

You will gain confidence if you approach people on the street