Ok, this is probably an easy one for all the abstraction gurus around here:) Is it possible for an abstraction to use tables (e.g. containing samples) which are defined in the patch which contains the abstraction?

Sure ! I don't know if that's really what you are asking, but you can use

[set thisTable<
|
[tabread~]

in an abstraction.

You can also just pass the table name as an argument to the abstraction:

[myAbstraction tablename]

Inside abstraction:

[tabread~ $1]

In addition, you can use [expr] to get the number of samples in the table:

[loadbang]
|
[symbol $1]
|
[expr size("$s1")]