This is a table I drew up to see where the VLA and VLBI might be able to resolve SNR in other galaxies, I've scaled the size and flux density of Cas A (an extreemly bright galactic SNR) and 3C 397 (a more "normal" galactic SNR) for the known distances.

I also have a text (comma separated) version which could be imported into a spreadsheet.

Nearby Galaxies which could contain SNRs:

          Cas A   3C 397          
Galaxy Distance (Mpc) Type Dec (J2000) VLA obs Size (") flux (mJy) Size (") Flux (mJy) Notes      
NGC6822 0.56 IrrIV-V -14 B,D,CnB,DnC 1.497 67.921 5.334 7.015 Skillman,Brooks, Matonick opt.  
IC1613 0.64 IrrV 2 B,D,C,CnB,B 1.310 52.002 4.667 5.371 Wilcots,Zhao,Lacey,Pedlar,Skillman  
M31 0.77 SbI-I 41 no? 1.089 35.925 3.879 3.711        
IC10 0.82 dIrr 59 B,C 1.016 31.295 3.621 3.232 Yang, Skillman, don't think they are SNRs
M33 0.84 ScII-III 30 Y 0.998 30.187 3.556 3.118 J. Moran H2O masers    
NGC300 2.10 SA(s)d -37 BnA,Cnb,CD,BC 0.399 4.830 1.422 0.499 Panutti, Lacey,Bosma, Duric  
UGC8638 2.30 D     0.365 4.026 1.299 0.416        
NGC253 2.50 Sc -25 AB 0.335 3.408 1.195 0.352 Jim Ulvestad, VLA VLBA?    
NGC5253 2.80   -31   0.299 2.717 1.067 0.281 Turner Ho Beck 1998    
UGC290 2.80 d     0.299 2.717 1.067 0.281        
IC342 2.90   68 ABCD 0.289 2.533 1.030 0.262 A. Cox, J. Turner, no SNRs?  
UGC7866 3.00 d     0.279 2.367 0.996 0.244        
UGC292 3.10 d     0.270 2.216 0.964 0.229        
M82 3.20 Irr2 69 Y 0.262 2.080 0.933 0.215 Muxlow 94 Merlin, Bartel 87 VLBI  
NGC2403 3.20   65 BnA 0.262 2.080 0.933 0.215 optical Lacey    
UGC8833 3.20 d     0.262 2.080 0.933 0.215        
UGC8651 3.40 d     0.247 1.843 0.879 0.190        
NGC7793 3.40   -32 BnA 0.247 1.843 0.879 0.190 Lacey VLA      
M81 (NGC3031) 3.60 Sab 69 BnA, A=>B 0.233 1.644 0.830 0.170 Matonick & Fesen    
NGC4736 4.00 Sab 41 A,B,C,D 0.210 1.331 0.747 0.138 DURIC,      
NGC4395 4.50   33 Y 0.186 1.052 0.664 0.109 General User      
NGC5204 4.80 Sm 58   0.175 0.924 0.622 0.095 Matonick & Fesen    
NGC4449* 5.00 I 44 Y 0.168 0.852 0.597 0.088 Lacey Goss Duric    
M101 (NGC5457) 5.40 Scd 54   0.155 0.730 0.553 0.075 Matonick & Fesen    
NGC6946 5.50   60 Y 0.152 0.704 0.543 0.073 Lacey Goss Duric, Matonick & Fesen  
Cep 1 6.00       0.140 0.592 0.498 0.061 Burton, Braun. HI detection only  
NGC5585 7.00 Sd 56   0.120 0.435 0.427 0.045 Matonick & Fesen    
NGC5471 7.20   54 A 0.116 0.411 0.415 0.042 in M101, J. Pedlty no paper  
NGC660 7.50   13 Y 0.112 0.379 0.398 0.039 Lacey Goss Duric    
NGC3447 10.70   16 not A 0.078 0.186 0.279 0.019        
NGC3448 10.70   54 C 0.078 0.186 0.279 0.019 Noreau Kronberg    
NGC3646   S 20 no         Has SN      
NGC5471                        
  1.00       0.838 21.300 2.987 2.200        
  2.00       0.419 5.325 1.494 0.550        
  3.00       0.279 2.367 0.996 0.244        
  4.00       0.210 1.331 0.747 0.138