I am sympathetic to your desires. I won't go into my rant about the 'fat society' we are experiencing these days and how society caters to those over weight. Instead I come to you as a 35 yo man that has never been able to pack on weight. I lift four days a week, I run 1.5 miles before my lifting and run 5-6 miles on my cardio day. I also have never weight more than 155 pounds, and at 5'11, feel am still very thin. I'm currently at 154.
In January I decided I was going to gain weight. I was tipping the scales at 144. I bought Prolab N-large II weight gain/protein mix, I also bought the Pure Protein bars (chewy chocolate chip are great) and started counting calories. Bottom line is that I wasn't eating enough through out the day. I am consciously taking 225 grams of protein per day, and eating 3500 calories. I'm up 10 pounds in 3 months, my waist size is down a tad but my chest, arms, back and legs are a little bigger. I'm also still at 6.3% body fat.
On top of the exercise I do regularly, I also actively coach my son's soccer team, play tennis and ride mountain bikes. This activity means I burn more calories than a lot of people, and on top of my overzealous metabolism, means I have a hard time putting on and maintaining weight.
I'm no pro, but I can share my meal plan:
`Breakfast, two hard boiled eggs, a whole grain breakfast bar and a protein bar.
`Mid morning, fruit; banana, apple or orange and a protein shake
(Work out during lunch)
`Lunch/post work out, leftovers from dinner before, today it's ribs and potatoe salad and a protein shake
`Mid afternoon, fruit and somce whole grain crackers, or a home made trail mix
`Dinner, whatever the wife makes but usually some low fat meal ie, chicken and veggies, or steak and potatoe and veggies
`Dessert, cake, pie, cookies, whatever
`Late night snack, usually 2-3 bowls of Capt'n Crunch, love that stuff!
The thing is, you have to eat big to get big(ger). I've got genetics and a crazy high metabolism on my side, I don't have to worry about bulking up too much. THis won't work for everyone but it works for me. I also don't live to eat, instead eat to live so the protein calorie drinks are my friend.
Good luck!