Need a hearty, meaty but easy appetizer

The meatballs sound perfect!

Other options could be a variety of sliced salami or summer sausages or even cold chicken wings.

I made Sausage rolls for a party this weekend.

Cooked Sausage and mushrooms and onions, put a little mustard on puff pastry, then add the sausage mixture slice and bake. They are flaky, yummy and full of protein. (No calories of course )

I've had to do this twice in the last week. The other day, I did mini Smokey Joes turkey hot dogs in BBQ sauce, the Pioneer Woman's Potluck Meatballs, and a cheese and cracker platter. Yesterday, I made meatballs in BBQ sauce and mini cheeseburger meatballs.

The rest is self explanatory, but I found the mini cheeseburger meatballs in Pinterest. I baked meatballs for 15 minutes and then added a 1/4 slice (so cut into squares) of cheese and bake for another 2-3 min. Let it cool about 5 minutes after it comes out of the oven. I topped it with a 4" skewer of a grape tomato, lettuce, and a square of bacon. Not one came home and they were really cute. I did the skewers of tomato, lettuce, and bacon ahead of time and they assembled really quickly. I served them room temp and they were good.  I like the turkey meatballs from Stony Brook Farms.

ETA:  found a picture!  Mini cheeseburger appetizers  

This was my first thought!

There is also little smokies, wrap in bacon and baked with brown sugar. You can do this the night before and then stick them in a crock pot the next day.

I like the grape jelly meatballs and everyone's suggestions sound great, too.

Something we often do (although admittedly, this is Jewish food) is split mini bagels or thin-sliced baguettes, spread with plain or herbed cream cheese and topped with a bit of lox (smoked salmon). You can also add a few capers or a bit of fresh dill or a squeeze of lemon. But anyway, they're fast to put together if you have everything ready to go.

Apple and sausage stuffed croissants
Queso dip with sausage or beef
Little smokies are always a hit

We have the same thing happen at our 4-H potlucks, during dinner time but a lot of light snacky food. So like you I tend to bring a meat or protein appetizer to help fill people up.

I usually bring meatballs or lil smokies. There is something else I bring but can't remember right now. I love all these ideas

Bacon-wrapped smokies

Will you have time to heat something before you have to leave? You could do the prep work the night before and pop into the oven to cook that evening.

Mini pasties:
Ground beef
Frozen hashbrown potatoes
Lipton onion soup mix

I eyeball this but the beef and potatoes are equal parts.

Make a batch of biscuit dough

Roll out bite size circles, fill with meat, fold over like a turnover.

Bake 350 until brown.

Serve with( shivers) ketchup.

Bacon wrapped, almond stuffed dates are easier than they might sound, especially if you used pitted dates. They can be baked the night before and either warmed up or served cold. I've made these with the goat cheese, but if I don't have any no one has complained. I also cut my bacon 3 pieces and find that is enought to wrap the dates. 

bacon wrapped, almond stuffed dates

Those mini cheeseburgers have been pinned Basket1lady - thanks for sharing!

Or try Chili Sauce instead of cocktail sauce - yum yum!

Could be - I thought Cocktail Sauce had more of a horseradish taste but next time I'm at the store I'll have to compare the two.

We're having this for dinner tonight. I'm hoping it tastes as wonderful as it sounds. I think it would be perfect for your event.