Place for experiments; artist with sketch being cross (11)
I believe the answer is:
labradoodle
'being cross' is the definition.
(I've seen this before)
'place for experiments artist with sketch' is the wordplay.
'place for experiments' becomes 'lab' (I've seen this before).
'artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'with' means one lot of letters go next to another.
'sketch' becomes 'doodle' (I have seen 'Rough sketch ' mean 'doodle' so perhaps 'sketch' could also mean 'doodle').
'lab'+'ra'+'doodle'='LABRADOODLE'
(Another definition for labradoodle that I've seen is " Cross".)