I can't find any YouTubes of Galician alboradas like you describe - they're simple two-parters - but this one is close to your description. And has several changes of mode.

X:102
T:Alborada de Pontecaldelas
M:2/4
Z:Richard Robinson 
%%ID:00000c0d
K:G
d4    edce |d3G   G2G2|d4    edce|d3G G2G2 |
g2gf  edef |g3d   edBd|gfed  edef|d3G G2G2 |
d4    d3e  |d2dB  cBcA|B2BG  AGAB|G8      :|
d2de =fefd |e=fed c2G2|c2cd _edec|d4  d4   |
B2Bc  d_edc|BcBA  G2B2|ABAG  FGAB|G8      :|
g4    g4   |fgfe  defd|g3d   Bcde|d3G G2G2:|
d4    d3e  |d2dB  cBcA|B2BG  AGAF|G8      :|
A3F   G2A2 |B3G   A2B2|c3A   B2c2|d4  d4   |
g2g=f defd |e=fed c2G2|e2dc  Bcde|d4  B2e2 |
d2cB  ABcA |BcBA  G2B2|ABAG  FGAB|G4  B2e2 |
d2cB  ABcA |BcBA  G2B2|ABAG  FGAB|G8      :|