I make a similar Mexican shrimp cocktail, but it's spendy to do so.

2-3 lbs shrimp
1 large can of baby clams
1-2 lbs of imitation crab meat
6 Avocados, diced
6 cucumbers, sliced then quarter diced
6 California green chilis, diced really small
6 Yellow chilis, diced really small
1 Bushel Cilantro
6 Tomatos, diced
Large Red Onion, chopped small
2lb Ketchup
Juice of 6 Lemons
Juice of 6 Limes
Salt/Pepper

Tapatio and Crackers!

Notes from over the years of making it:

Sear the Shrimp, don't use pre-cooked. If seared in butter, drain juice (butter fat will coagulate in the cocktail)
Wash clams really good
DO NOT add seeds from peppers, do not use Jalapeno's
Mix the veges as you add them
Fresh tomatoes only, not canned
Lemon/Lime juice in bottled form is fine <--- is key to getting that perfect tang
Red onion looks nice, sweet onions taste better
Add Avocados and Tomatoes at the end of prep, after seasoning to taste (so you don't bruise them up)

Let sit overnight for best results.
Cost is usually $80 or so.
DO NOT TAKE ANYWHERE EXCEPT TO FAMILY FUNCTIONS. Otherwise, there will be a party invite every week